As already mentioned, the decompression feature can't be retrofitted. I have two saws that have the decompression button, and one that doesn't. I can barely pull the handle of my Husqvarna 394XP without the button in. The stihl 361 is barely any different at all with or without the button.
If the saw is harder to start now than when you bought it, something is wrong. If you don't already do it, you need to make sure that you're greasing the crankshaft bearings when you use it; I know a few folks that I've never seen grease theirs.--I don't know if its the same on your saws, but on mine, there's a grease fitting on the shaft itself, on both the starter side and the clutch/drive spur side. I run a little more oil in my gas on the 394XP than is recommended, mostly because I often mill lumber with it. I run about 40:1 instead of 50:1 gas/oil mix. When you're using a saw for long periods of time at wide open throttle, it is more stressful on the saw, which is usually meant to cut for a few seconds, then idle, cut, idle, etc. A little extra oil in the mix can't hurt. Most homeowner saws weren't meant to run at full rpm for minutes at a time, which is what a lot of turners need to do to cut big blanks, and most have smaller saws, stihl, husky, or whatever brand. Every mfr. has "homeowner grade" and "pro grade". Thats why there's so much difference in price between certain stihl or husqvarna models that seem on paper to have very similar if not exact specifications. I run my saws a lot, and two do happen to be professional saws, and were very expensive, so I want them to run for as long as possible. The extra oil is a little insurance; its not fun to breathe in, but its a lot better for the saw if you run it this way frequently. It's easy to burn out a saw by not having enough oil in the mix, and running it hard. The rings scratch the cylinder & can become seized, or if water gets into an iron cylinder, etc.
I hope your saw doesn't have something serious wrong with it. I know that's gonna hurt the wallet to fix, or replace!
If the saw is harder to start now than when you bought it, something is wrong. If you don't already do it, you need to make sure that you're greasing the crankshaft bearings when you use it; I know a few folks that I've never seen grease theirs.--I don't know if its the same on your saws, but on mine, there's a grease fitting on the shaft itself, on both the starter side and the clutch/drive spur side. I run a little more oil in my gas on the 394XP than is recommended, mostly because I often mill lumber with it. I run about 40:1 instead of 50:1 gas/oil mix. When you're using a saw for long periods of time at wide open throttle, it is more stressful on the saw, which is usually meant to cut for a few seconds, then idle, cut, idle, etc. A little extra oil in the mix can't hurt. Most homeowner saws weren't meant to run at full rpm for minutes at a time, which is what a lot of turners need to do to cut big blanks, and most have smaller saws, stihl, husky, or whatever brand. Every mfr. has "homeowner grade" and "pro grade". Thats why there's so much difference in price between certain stihl or husqvarna models that seem on paper to have very similar if not exact specifications. I run my saws a lot, and two do happen to be professional saws, and were very expensive, so I want them to run for as long as possible. The extra oil is a little insurance; its not fun to breathe in, but its a lot better for the saw if you run it this way frequently. It's easy to burn out a saw by not having enough oil in the mix, and running it hard. The rings scratch the cylinder & can become seized, or if water gets into an iron cylinder, etc.
I hope your saw doesn't have something serious wrong with it. I know that's gonna hurt the wallet to fix, or replace!